[Perf] Linux/arm64: 1 Improvement on 7/3/2026 7:11:21 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | arm64
OS | azurelinux 3.0
Queue | CobaltAzureLinux
Baseline | [fe5e47348f86013bbe8f3041e56f5208cd632e53](https://github.com/dotnet/runtime/commit/fe5e47348f86013bbe8f3041e56f5208cd632e53)
Compare | [e6428cb16317ce994463cb132690ec728991edd9](https://github.com/dotnet/runtime/commit/e6428cb16317ce994463cb132690ec728991edd9)
Diff | [Diff](https://github.com/dotnet/runtime/compare/fe5e47348f86013bbe8f3041e56f5208cd632e53...e6428cb16317ce994463cb132690ec728991edd9)
Configs | CompilationMode:tiered, R2RType:r2r_interpreter, RunKind:micro

### Improvements in System.Collections.CtorDefaultSize<String>

Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio
-- | -- | -- | -- | -- | -- | -- | -- | --
|

• [ConcurrentBag - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

![graph]()
[Test Report]()

### Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

```cmd
git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Collections.CtorDefaultSize*'
```

### System.Collections.CtorDefaultSize<String>.ConcurrentBag

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

[Profiling workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/profiling-workflow-dotnet-runtime.md)
[Benchmarking workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/benchmarking-workflow-dotnet-runtime.md)

Start with the benchmark source at src/benchmarks/micro/libraries/System.Collections/Create/CtorDefaultSize.cs and run the provided benchmarks_ci.py command. Review the linked test report and profiling workflow documentation to understand the arm64 improvement; completion is not defined until the runtime cause and any required change are identified.

Written by the indexing model from the issue text.